


Castiel's Secret

by thewinchesterlifestyle



Category: Supernatural
Genre: Alpha Jimmy, Alpha Michael, Bestiality, Bottom Castiel, Butt Plugs, Castiel and Jimmy Novak Are Twins, Exhibitionism, Knotting, M/M, Omega Castiel, Other, Outdoor Sex, Rough Sex, Sibling Incest, Teen Castiel, Teen Jimmy, Threesome, Top Michael, Twincest, Underage - Freeform, Voyeurism, blowjob
Language: English
Status: Completed
Published: 2016-07-26
Updated: 2016-07-26
Packaged: 2018-07-27 00:15:15
Rating: Not Rated
Warnings: Underage
Chapters: 1
Words: 3,456
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7595809
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: <blockquote class="userstuff">
              <p>When Castiel presented as an Omega he desperately worked to hide it, researching every possible option until he stumbled upon an interesting solution.</p>
            </blockquote>





	Castiel's Secret

**Author's Note:**

> Written for a prompt.
> 
> Castiel/Jimmy: 15  
> Michael: 19

Castiel felt his heart stutter to a stop when he realized exactly what he was. An Omega. The first thing he did was seek out everything he could to disguise his scent and give off the impression he was a Beta. Anything to keep the Alphas away and give himself a little more time to try to find a mate of his own. But that didn’t stop his body from producing slick or stop the scent of some Alphas causing him to become aroused.

So Castiel researched toys and anything that wasn’t him giving away that he was an Omega. It was on the third day of him spending the morning fingering himself in the shower until he came that he stumbled across a simple answer that gave him what he wanted.

Dogs.

They had knots and he didn’t have to give away exactly what he was because his family owned several dogs who were the perfect size. All of the Omegas in the videos he watched were moaning and coming on the knot of the dog mounting them. It was the perfect solution and the next day he pretended to be sick.

Two hours after the house had cleared out, his twin worried for him but still going to school, Castiel grabbed a plug and headed outside towards a spot he knew would conceal him on the off-chance someone came back by.

The young Omega stripped himself down as he rested on the grass before calling out to them. He could hear excited barks as they came running and they licked at his face, bodies shaking with happiness, until one of them caught his scent in the air.

The dog went around behind him and started to sniff at his ass before a whine escaped. A tongue licked at him and Castiel felt a jolt of arousal burning in his gut when that warm wet tongue swiped across his hole. “ _Oh_.” his mouth dropped open and his eyes widened in surprise as he shifted himself. Warmth curled in his belly and more slick started to leak out.

Carefully he moved into the position he’d seen the Omegas in the videos take and spread his legs for support as Domino lapped at his hole with enthusiasm. The sensation had Castiel hard and leaking as he whined before trying to hold his ass up higher. “Come on boy, up.” he patted his back and it was all the dog needed.

After all this wouldn’t be their first bitch.

Castiel could feel Domino’s cock, free from its sheath, brushing against him as legs wrapped around his waist. Nails scraped against the bare skin there and he could feel Domino thrusting against his ass. The cock slipped through the slick there and when it finally caught in Castiel’s hole the Omega’s breathing stopped. Everything slowed down as hot breath brushed the back of his neck, teeth barely grazing him, before Domino slammed his cock inside.

The sudden feeling of being split open on a cock had Castiel’s mouth dropping open and a high sound escaping as Domino started fucking forward quickly. To the young Omega it was nothing like his fingers and the feeling had him moaning even as he burned at the stretch. His body and his instincts were screaming at him to be bred full. He wanted it so badly and he wondered what his Heats would bring.

Pleasure was starting to burn low in his gut and when the dog’s knot started to grow, catching on his rim, Castiel felt himself falling towards the edge. The knot grew and tied them together as Castiel came across the grass with a moan with his ass clamped down around the dog’s knot. It earned a low rumbling sound and then he was feeling hot come pouring into him.

He could feel the way his inner muscles were almost greedily milking the knot buried inside his aching ass.

Everything in him gave away and he collapsed on the cool grass as Domino turned around to wait out his knot. “Oh wow.” he gasped and whined low at the tug of a knot in his ass. “That’s what I’ve been missing.” it was wondering and he looked over at the other dogs, both of them bigger than the one tied with him. His cock twitched with interest and he clenched around the dog as more of Domino’s hot seed spilled into him.

By the time the other dogs had a turn he was a pleased and happy fucked out mess on the grass. Seed and slick leaked from his puffy hole as he fumbled with the plug he’d brought. It kept everything inside him so he could get back inside and clean himself up without anyone the wiser.

After that day he would try his hardest to go outside to get knotted at least once before coming back inside. Most of the time it was dark out and those were his favorite knottings as his lack of sight seemed to enhance the feeling of a cock working inside him and fur brushing his bare skin.

Nighttime was also when he could manage the most knots with the cover of darkness hiding him and only the sounds of his low whining, the dogs panting and cocks working through the mess in his ass could be heard.

His family made comments about how he didn’t seem as stressed out and how much more relaxed he seemed but Castiel kept his secret. He kept covering up his scent, wearing a plug most of the day to keep his slick inside and when he could he sought out the dogs to sate his need. They helped, some, with his increasing instinct to present to an Alpha for a proper knotting and breeding that the dogs couldn’t give him.

No one knew about his activity or his designation until he was caught getting fucked by Jack, Michael’s dog, and then his secret was out. Castiel was lost to the feeling of the dog’s cock working through the mess the other two had already made, knot tugging on him as it swelled, when he heard a gasp.

Castiel clenched his eyes shut and tried to move out from under the dog but a snarl had him freezing as teeth lightly closed around the back of his neck. Jack’s hips seemed to pick up speed as he thrust quicker until his knot was locking them together. Castiel came with a sharp cry at the feeling of the largest knot of the family dogs stretching him open.

He couldn’t hold back the moan and shame choked him as he lowered himself to the grass to wait out the last knot. It wasn’t until hands were touching his face that he looked up to meet identical features to his own.

Jimmy

“You’re an Omega?” there was surprise and wonder in the tone as Jimmy moved to look at the place that Castiel’s ass was split open on a knot. “Fuck that was hot, Cas.”

That was when Castiel could smell Alpha arousal coming from his twin and he could see Jimmy’s cock straining against his pants. “You’re an Alpha?”

“Presented earlier today…that’s why I came home.” another sound escaped Jimmy’s lips as he stared down at his twin. As he stared at his twin who was an Omega and currently being knotted by a  _dog_. “I’m glad I did.”

“Jimmy.” Castiel’s mouth worked and he moaned as another load poured into his ass as he clenched around the knot. The hard ball of Jack’s knot kept him stretched open until it finally popped free. By that point Castiel was hard again and staring at his twin with obvious need. “Please.” he doesn’t have to specify what he wants because Jimmy  _knows_.

Fingers fly to his pants and Jimmy has them down in record time as he shoos one of the dogs out of the way. It’s obvious he isn’t going to wait out another fucking and knotting by a dog.

His thumb moves over Castiel’s wet hole and earns a high sound that Castiel can tell affects him by the increase in Jimmy’s arousal. “Cas. You’re perfect.” Jimmy teased his hole for a little longer, dipping his fingers inside and weighing Castiel’s balls before he moved to mount him.

Jimmy’s cock easily pressed inside, into wet and tight heat, as he moaned at the feeling. It felt perfect and he bottomed out to Castiel’s breathy and needy sounds. “Feels so good.” and Castiel has spent weeks getting fucked by dogs so he knows this feels just as good if not better.

He doesn’t get the point of toys and when Jimmy starts snapping his hips forward in an uneven rhythm, searching for one that works, Castiel lets himself get lost in it. It is nothing like the dogs and yet there are similarities.

Castiel focuses on the slap of balls against him, the feeling of his ass stretched open by another cock and when Jimmy’s knot swells he enjoys that feeling. He lets himself get lost in it.

And when Jimmy’s knot locks them together and that first load of seed pours into him he comes again with a broken sound that none of the dogs had managed to pull from him. Long fingers gripped him as Jimmy continued to rut against his ass, circling his hips, to send more sparks of pleasure through Castiel’s shaking body.

“Wow.” Jimmy breathed, body pressing Castiel into the grass, as the twins lay sprawled out and tied together. “Can we do this inside next time?” he asked and Castiel blearily reached back to grab onto him.

“Wherever you want.” his voice was wrecked and Jimmy grinned against him as his cock released another load into his twin. In a house full of Alphas, hiding what he was, the knowledge that Jimmy would take care of him had relief flying through him.

“We’ll have to sneak in a dog a few times.” Jimmy nuzzled against him and thought of biting Castiel’s neck to claim him but he held back the instinct since this was his twin. “You should see yourself…Jack was just going crazy.”

“Feels good.” Castiel admitted as he sighed out and clenched around his twin’s knot as his ass continued to milk the Alpha for every single drop. “Love knots.” it had Jimmy moving in short little thrusts against him again as he enjoyed the feeling of Castiel tight around him.

“Course you do, Cas, you’re an Omega. Omegas love getting fucked open on knots.”

* * *

 

Jimmy had noticed after a few times that Jack went wild if Jimmy had knotted Castiel first and that was the kind of enthusiasm he wanted to finally catch on tape. The camera was set up, aimed for the bed where his Omega twin was presenting his ass to the air, as Jimmy fingered Castiel open for his cock.

Jack was watching from the floor, whole body shaking, as he waited for his turn with the whining Omega. “You’ll get your turn, Jack.” Jimmy’s voice was rough as he pulled his fingers out and guided his cock inside as Castiel’s legs shifted apart in the hopes of getting the Alpha deeper. “I can see his cock sticking out. He wants to fuck his  _bitch_.” the word had Castiel’s throat working as he clenched around Jimmy. “Looking forward to being knotted?”

Jimmy reached forward to grip at Castiel’s neck until the Omega under him went completely pliant in his hold as he started to snap his hips forward into wet heat.

Neither of them noticed one of their brothers coming into the room and watching from the corner silently as Jack’s eyes darted from the Alpha to the two on the bed.

Instead the only sounds they were aware of was the slap of Jimmy against Castiel’s ass as the young Alpha fucked quickly, panting and groaning as Castiel’s hole fluttered around him, trying to reach his knot. “So glad you’re an Omega, Cas.” Jimmy breathed as Castiel tried to shifted himself back into it while his fingers knotted in the sheets. “Love fucking you. Good practice for later.”

“Please Jimmy  _please_.” Castiel’s voice was low and the thick scent of Omega arousal seemed to saturate the air as Castiel’s cock ached.

"You’re just wanting Jack to knot you…that’s why you want me to hurry, isn’t it? Like the dirty feeling of being fucked by an animal who only sees you as a  _hole_.” and Castiel whimpered even as he wondered where Jimmy had heard that kind of talk. “Just like those Omegas in the videos I found on your computer.”

Castiel’s face flushed but he nodded anyway, “Knot please Jimmy…just want a knot.” he was babbling now as he felt Jimmy’s knot swelling inside him as his twin ground against him.

When it tied them together Castiel felt Jimmy touch his cock before he came all over the sheets with a broken cry.

It was when Castiel slumped against the sheets with Jimmy lazily grinding against him that their brother made himself known. “It’s a pity you didn’t both present as Omegas. Wouldn’t that have been perfect?”

The voice had both jerking and Castiel shoving his face into the sheets as Jimmy growled. “How long have you been there?” Jimmy demanded even as his cock released inside Castiel.

"Long enough to become very interested in the next part.” his grin was sharp and Jimmy could smell the arousal coming from the other Alpha. “I’ve never seen an Omega fucked by a dog in person.” he glanced down at Jack, “And what a treat that you’re using my dog.”

Michael stepped from his position to come closer to them, looking the twins over with appreciation, as Jack’s tail started to wag.

“Excited boy?” he asked as he pet the dog’s head before he dropped down into one of the chairs in the twin’s room. “I know I am.”

Castiel glanced up at his older brother, cheeks flushed and lips parted as his ass flexed around his twin’s knot, to see dark eyes watching him sharply. “Michael?” there was a cautious note in his voice, “Are you going to tell our parents?” that was his main concern.

“Why would I ruin this?” he asked and his voice softened slightly, “If you don’t want to let them know who am I to say something about it?”

It had both twins relaxing and Castiel offering a hesitant smile as Jimmy resumed his task of grinding against his twin until his knot went down.

And the whole time Michael sat there watching them, arousal thick in the air, until Jimmy’s cock slipped from Castiel and he watched his dog scrambling to get onto the bed.

“Enthusiastic.” he chuckled as Castiel whined at the feeling of a tongue lapping at his ass, dipping inside to get Jimmy’s come, as Jack’s whole body seemed to still while he focused on the task. “Omegas really like you eating them out.” Michael spoke softly to Jimmy who stared at him, “If they love anything more than being caught on a knot, fucked full, it is the feeling over someone eating them out.”

He walked forward and ran a hand through Castiel’s hair as his dog continued to make wet noises as he kept going.

“Come on Jack. Mount your bitch.” he patted Castiel’s back, watched the Omega shifting slightly in preparation, as slim hips seemed to cant perfectly for Jack to mount.

The large dog climbed onto Castiel, legs locking around him as his nails cut into the Omega’s sides, before he started desperate thrusts trying to get his cock inside.

Michael moved around so he could watch and he smirked when Jack released a sound as his cock caught on Castiel’s puffy hole. “There we go.” he breathed and watched as Jack slammed inside with an excited sound.

Both Alphas watched as Jack pistoned his hips, panting and releasing sounds, as his cock worked through the mess of slick and come he hadn’t been able to lick out.

“It’s even better watching it in person.” Michael breathed and Jimmy could see the way his brother’s cock was straining against his pants. “I could pop a knot just watching. Look at his face, Jimmy.” Michael gripped his younger brother’s face to direct him, “Omegas are made to be fucked…look how blissed out Cas is with a cock inside him.”

Jimmy might have protested but the sight of Castiel lost in pleasure and moaning as Jack fucked him had his cock twitching with interest. “Oh ohhhh…” Castiel’s mouth worked and both Alphas watched as he came not on a knot but just from Jack’s brutal thrusts. His arms were shaking and then a whimper escaped as Jack’s knot swelled before catching in his ass.

The dog rumbled as his cock started to spurt inside Castiel and then he was turning them ass to ass just in time for Castiel to collapse against the sheets with his ass still slightly canted up.

“You came on just his cock.” Michael murmured as he pet Jack’s head and his dog’s tongue lulled out with happiness. “Fuck. That was hot.”

Jimmy was still staring at his brother as Castiel released a pleased sigh, ass tight around Jack’s knot, while the dog rumbled at the pressure squeezing him.

“Do you want another knot, Cas?” Michael asked as he moved around to look at Castiel’s flushed face. “Hmmm?” he tugged on Castiel’s mussed hair and grinned when his brother seemed to press into his touch.

“Another knot?” Castiel blinked at him, eyes glassy and dazed, before he he glanced down to see their brother’s cock pressing against his pants. “Oh.” his eyes went wide and Jack rumbled when Castiel’s ass clenched down on him unexpectedly.

“Want me to fill you up, baby brother? Do you think you can handle a more mature Alpha cock and knot? I know you’re still young but your hole was made to take the biggest Alpha cocks. That’s what Omegas do.”

Castiel nodded and waited until Jack’s knot popped free causing his come to leak out. “Oh.” Castiel’s legs were shaky and Michael stroked down his bare sides.

“We’ll try a different position for you.” Michael smirked, stripping his clothes, before he shifted onto the bed and reached forward to drag Castiel to him.

He pressed a few fingers inside Castiel’s wet hole, stretching and teasing, until he felt that Castiel was ready for a larger cock. His fingers withdrew and then Michael was guiding Castiel down on his cock, biting his lip as wet heat wrapped around him, until he was buried completely inside Castiel.

“ _You’re so tight_.” his voice was low as Castiel whined at the stretch, “I can see why Jimmy was keeping you to himself and the dog.” his fingers moved down to grip Castiel’s hips and then he was bouncing the Omega down onto his cock. “Then again you’re still so small it shouldn’t be a wonder that your hole is like a vice around my cock.”

Moans and gasps escaped as Castiel’s body moved up and down the length of Michael’s cock. His legs shook, mouth dropped open, as he clung to Michael.

“Going to take my knot? Going to be split open on another one?” his voice was rough and Castiel nodded jerkily as they kept moving together. The movements were quick and hard and desperate until Michael started to ground him down onto his cock until the knot pressed past Castiel’s rim to lock them together.

His fingers tightened and Michael forced himself not to bite the inviting neck in front of him as his cock started to spill his load into wet heat.

Instead he shoved his face against Castiel and gripped him as the Omega whimpered on his cock. “Come on Jimmy. Think Cas needs some help.” Michael watched Jimmy climbing onto the bed and Jimmy didn’t even bother stroking Castiel with his hand. Instead he leaned down and swallowed Castiel down without a sound.

Jimmy’s head moved as he set to work sucking Castiel off until everything in Castiel tightened and he came down his twin’s throat with a wail while Michael continued to pump his come into his ass. “Wow.” he went completely limp against Michael as Jimmy pulled off with a pop so he could lean forward to nuzzle against his twin.

“It really is a shame it’s only one of you that turned out to be the pretty Omega slut in the family. Two would have made things more interesting.” Michael spoke as he held Castiel’s hips tighter and continued to grind himself up against Castiel’s plump ass.


End file.
